emberjs/ember.js — pull request #9551 by stefanpenner (2014-11-12 06:12:48+00:00)
Title: [Bugfix Beta] Improve performance of Mixin creation by 50% -> 60% (when ...

...mixins are composed of multiple mixins)

* shape Mixin correctly (properties set in constructor)
* don’t pass arguments object around
* prefer new Mixin(args, properties) internally